Suggestions from Tatiana Chammaro (UBC Master's Student)

R1:  I don’t know if the Global Footprint Network has those kinds of data but they have an open data portal. Poore & Nemecek paper (2018) is a big one. Seems like the largest meta-analysis to date? But I might be wrong. Still worth a look!

R2: Hestia has crop specific and country specific data https://www.hestia.earth 

R3: And dataField is easy enough to use, has a bit more granularity for GHG emissions than Poore but primarily looks at GHG not the rest dataFIELD

R4: Have you tried Balsher? He was a postdoc with Milind and I think he was doing some modeling work on GHG emissions from agriculture in India.. maybe he might be able to point you / your friend to the right direction! https://www.balshersidhu.com